KR20080066910A - Hydrostatic piston machine - Google Patents

Abstract

The invention relates to a hydrostatic piston engine (1) having a driveshaft (2) which extends through a cylinder drum unit. In this hydrostatic piston engine, cylinder recesses (18, 19) are arranged in the cylinder drum unit. Rotationally fixedly connected to the driveshaft (2) are pistons (16, 17) which are arranged so as to be moveable in the cylinder recesses (18, 19). The cylinder drum unit is centred on a bearing (32, 32') which is provided on the driveshaft (2). The cylinder drum unit (20, 21) is composed of a cylinder drum (20, 21) having a plurality of cylinder recesses (18, 19) formed therein.

Description

Hydrostatic Piston Machine

The present invention relates to a hydrostatic piston mechanism having a cylinder drum unit having a penetrating drive shaft, wherein the piston is disposed on the drive shaft in a torsion-proof manner.

Hydrostatic piston mechanisms through which drive shafts penetrate first and second cylinder drum units are known from the invention described in PCT / NL03 / 00017. A carrier plate is fixed to the drive shaft symmetrically between two cylinder drum units. Pistons movably mounted in the cylinder space of the cylinder drum unit are arranged on opposite sides of the carrier plate. The axis of rotation of each of the cylinder drum units is located at an angle determined by the angle of the drive shaft. In this way, the piston connected to the drive shaft in a torsion-proof manner performs a stroke-like movement in the cylinder space. The cylinder space is provided in a separate cylinder which is supported on a conventional drum plate and forms a cylinder unit together with the drum plate. In order to prevent the cylinder from being lifted from the drum plate, a retaining device is provided which allows radial movement of the cylinder. This arrangement, which is entirely movable, allows for the required compensation of the cylinder due to the fixed arrangement of the piston of the carrier plate and the inclination angle of the cylinder drum unit with respect to the axis of the drive shaft.

The above mentioned arrangement has the disadvantage that the centrifugal force acting, in particular in the case of a high speed rotational speed, can lead to a pitching motion in the parts of the cylinder. Even if the cylinders are individually provided to contact the drum plate via the retaining device, there is a significant amount of wear since the support surface of the cylinder is small relative to the forces acting, causing a large number of parts to move relative to each other. do.

It is an object of the present invention to provide a hydrostatic piston mechanism which avoids the above mentioned disadvantages resulting from the interaction of a large number of cylinder drum unit components.

In the hydrostatic piston mechanism according to the invention having the features according to claim 1, the cylinder drum unit also has a drive shaft therethrough. In the cylinder drum unit, the pistons passing through the cylinder gap are connected to the drive shaft in a torsion-proof manner. In contrast to the prior art, the cylinder gap is arranged to be connected in the cylinder drum forming the cylinder drum unit.

Therefore, such a cylinder drum, which is designed in a compact form, is generally centered on a bearing provided in the drive shaft. The individual cylinder gaps in the cylinder drum therefore do not have any independent motion. Conversely, the centering of the cylinder drum with respect to the axis of rotation of the drive shaft is achieved. Since the cylinder drum itself is designed as a one-piece, the individual cylinder gaps cannot generate any pitching motion when centrifugal force is applied.

Since the pitching motion of the individual cylinders is prevented, the wear occurring will be reduced. It is also possible to prevent canting in the direction of rotation which may occur in the individual cylinders, especially when the rotational movement of the cylinder drum unit is caused by a piston arranged inside the cylinders.

Further advantages of the hydrostatic piston mechanism according to the invention are shown in the dependent claims. Connecting the piston to the drive shaft via segmental connections has particular advantages. The torsion-resistant connection of the piston to the drive shaft via the segmental connection has the advantage that the compensation in different directions does not have to occur depending on the position of the cylinder. In contrast, the movement of the compensation is achieved by a piston with a different inclination with respect to the axis of the drive shaft, which is made possible by the segmental connection.

It is also advantageous for this to provide a piston having a spherical head which is coupled to a drive shaft or a corresponding spherical gap in a carrier plate connected to the drive shaft. In this case, the carrier plate can be designed as a radial extension on the drive shaft itself, for example a one-piece forging. It is also conceivable to have a toothing system on the drive shaft which is coupled to the separately produced carrier plate to form a torsion-resistant connection with the carrier plate. As a result of the installation of the segmental connection between the piston and the drive shaft, the inclination of the piston shaft with respect to the drive shaft shaft can occur. At the same time, a direct, torsion-proof connection between the drive shaft and the piston is achieved by the piston being fixed to the carrier plate in the form of a ball joint.

In order to prevent the rotation of the piston shaft from being blocked by contacting the cylinder shaft wall when the piston penetrates the cylinder gap, a cone is provided between the sealing portion and the segmental connection on the piston. The angle of the cone opening preferably corresponds to the intended maximum inclination angle of the cylinder drum.

The centering of the cylinder drum is preferably accomplished by a bearing mounted on the drive shaft. For this purpose, the central through-aperture of the cylinder drum, which is preferably designed as a bore, interacts with the bearings arranged in the drive shaft in a centring manner. Under these conditions, the bearing is preferably installed on the drive shaft surface as a spherical drive shaft portion.

According to one simple embodiment, the torque between the cylinder drum and the drive shaft can occur via a piston disposed in the cylinder gap. According to one preferred embodiment, an entraining element is provided between the spherical drive shaft portion and the cylinder drum. The cylinder drum and the spherical drive shaft portion are connected to each other in a torsion-proof manner by the joint element. Under these conditions, it would be more desirable if the joint element was fixed to the drive shaft and engaged in an entraining groove in the cylinder drum. The provision of joint grooves in the perforations of the cylinder drum allows the inclination angle of the cylinder drum axis to be varied with respect to the axis of rotation of the drive shaft.

It is also conceivable to arrange the cylinder drum in a fixed manner without arranging the joint groove in the area of the spherical drive shaft. Thus, the joint groove is disposed corresponding to the spherical drive shaft portion. It is also possible to have a plurality of joint elements which are preferably uniformly distributed in the periphery.

In order to ensure the best sealing, a piston ring is preferably arranged in the piston seal on the piston. The piston ring is designed, for example, as a steel ring inserted into a corresponding groove in the side of the piston in the region of the sealing part. Likewise, the piston ring is preferably designed in a spherical shape on the outside of the piston.

Another possible way to improve the sealing between the piston and the corresponding cylinder clearance is to install a thin-walled piston shaft in the area of the sealing part. This kind of thin-walled piston shaft in the area of the sealing part is able to elastically expand the piston shaft as a result of the spreading of the pressure inside the cylinder as a result of the outer cylinder acting as a seal against the cylinder clearance. Make sure This can be done in a particularly simple way by means of a gap in the piston, which is located on the side facing away from the segmental connection.

In order to prevent the piston from being lifted from the carrier plate during the suction stroke, a retraction disc is preferably provided which axially holds the pistons of the carrier plate. Under these conditions, the shrink disk is arranged in such a way that the inclination of the piston with respect to the carrier plate is not disturbed. The retractable disc wraps the piston in a manner that acts as a component of the segmental connection. For this purpose, a gap of the contracting disc is provided which accommodates the head of the pistons and has a spherical outline.

Preferred embodiments of the hydrostatic piston mechanism according to the present invention are shown in the drawings and will be shown in detail in the following detailed description of the invention. The contents shown in the drawings are as follows.

1 shows a longitudinal cross section of a first embodiment of a hydrostatic piston mechanism according to the invention.

Figure 2 shows a longitudinal cross section of a second embodiment of a hydrostatic piston mechanism according to the invention,

FIG. 3 is an enlarged view of part 3 (PART III) in FIG. 2.

A longitudinal sectional view of the first embodiment of the hydrostatic piston mechanism 1 according to the invention is shown in FIG. 1. The hydrostatic piston mechanism 1 has a drive shaft 2 mounted in a housing consisting of a first half portion 3 and a second half portion 4. The first half portion 3 and the second half portion 4 of the housing are installed in a substantially pot shape. Under these conditions, the perforations 5 are installed in the first half 3 of the housing. In the embodiment shown, the perforations 5 are designed with stepped bores. The end of the drive shaft 2 with tooth system 6 protrudes through the perforation 5.

The first drive shaft bearing 7 is arranged in the stepped perforation 5. The first drive shaft bearing 7 is designed as a tapered roller bearing. The stepped perforations 5 are also provided with a sealing element for sealing the drive shaft 2 with respect to the first half 3 of the housing.

At the opposite end of the housing, a stepped blind bore 8 is provided in the second half 4 of the housing. Similarly, a second drive shaft bearing 9, which is installed as a tapered roller bearing, is arranged in the part of the stepped blind bore 8 which faces the inner space of the housing.

The first half 3 and second half 4 of the housing are provided with circumferential flanges 10, 11, respectively. The first half part 3 and the second half part 4 of the housing are screwed against each other at the flanges 10, 11 by screws 12.

The carrier plate 13 is disposed almost centered inside the housing on the drive shaft 2. In the embodiment shown, the carrier plate 13 is designed in one-piece with the drive shaft 2.

Spherical gaps 14, 15 are integrated in the carrier plates 13 on both sides in the form of joint sockets. Pistons 16 and 17 having a ball-shaped head at their ends are inserted into the spherical gaps 14 and 15. Thus, the segmental connection formed between the piston and the carrier plate 13 will be described in detail again with reference to FIG. 3 described below. The pistons 16 and 17 are designed identically. For clarity, reference numerals 16 and 17 each refer to only one piston of the group of pistons interacting with the cylinder drums 20 and 21.

The piston 16, 17 has an end facing away from the segmental connection between the piston 16, 17 and the carrier plate 13, with the first cylinder drum 20 and the second cylinder drum ( 21) It protrudes into each cylinder gap 18,19. Inside the cylinder drums 20, 21, a plurality of cylinder gaps 18, 19 are arranged on the first and second circumferences, respectively, parallel to each other. The normal circumference of the first cylinder drum 20 and the normal circumference of the second cylinder drum 21 are preferably the same and correspond to the circumference on which the spherical gaps 14 and 15 on the carrier plate 13 are arranged. .

In each case a cylinder volume is provided between one conventional circumferential cylinder gap 18, 19, in which a corresponding piston 16, 17 is arranged. The cylinder drums 20, 21 are arranged in such a way that they are inclined with respect to the axis of rotation of the drive shaft 2. When the rotation of the cylinder drums 20, 21 and the drive shaft 2 occurs, each of the pistons 16, 17 performs a stroke-type movement in the corresponding cylinder gaps 18, 19. Thus, the cylinder volume provided is periodically reduced and expanded. Each of the cylinder drums 20, 21 is supported on each of the slanting discs 22, 23. In the illustrated embodiment, the inclined discs 22 and 23 are arranged in a fixed manner, such that the first and second cylinder drums 20 and 21 have a constant inclination angle with respect to the drive shaft 2 axis. However, it is likewise possible to support the cylinder drums 20, 21 for each of the adjustable tilted discs, thereby designing the stroke volume in a settable manner. In this case, in particular, it becomes possible to independently adjust the inclination of each of the first cylinder drum 20 and the second cylinder drum 21. Another possibility is in each case to provide a fixedly set angle to one of the cylinder drums 20, 21 and a variable pivot angle to the remaining cylinder drums 21, 20.

The embodiment shown in each case is for two pumps or two motors. In the figures, features that are only described for one aspect will be provided with corresponding reference numerals having apostrophes on the opposite side as well.

The following embodiment is for the unit of the instrument shown on the left side in FIG. 1, which consists of an inclined disc 22, a first cylinder drum 20 and a piston 16 which makes stroke-like movement therein. . Embodiments deal with the second unit of the instrument in a similar manner, shown on the right side of FIG. 1. In each case the corresponding components are arranged symmetrically with respect to the central plane 26.

The first cylinder drum 20 is provided with a running face 25 for supporting the support surface 24 of the inclined disk 22. In order to prevent the inclined disk 22 from being twisted, a locating pin 27 is fixed to the housing part 3 of the first potted form on the bottom surface 30 of the housing part 3. As the cylinder drum 20 rotates, the cylinder gap 18 is periodically connected via the cylinder bores 28 to control the aperture of the inclined disc 22, not shown. In each case in the illustrated embodiment, the pivot angle set in a fixed manner with respect to the first cylinder drum 20 and the second cylinder drum 21 is such that the first inclined disc 22 and the second inclined disc 23. Is provided. The inclination angle of the cylinder drums 20, 21 with respect to the drive shaft 2 axis is determined by the wedge shape on the inclined discs 22, 23. The inclined disc 22 has a bearing face 29 which allows it to rest on the bottom 30 of the first half 3 of the housing.

The first cylinder drum 20 has a central drilling portion 31 which is designed as a cylinder bore. The first cylinder drum 31 is supported against the bearing of the drive shaft 2 by the central drilling portion 31. The bearing of the drive shaft 2 is provided as a spherical outer portion 32 on the outside of the drive shaft 2. In the embodiment shown, the spherical perimeter 32 itself is made directly by the shaping of the drive shaft 2. As a bearing, the use can also be made of attachment elements with a spherical outline. In this case, the use can be made of other materials for installing the bearings and for the drive shaft 2 itself, for example to improve the emergency actuation characteristics in case of lack of lubrication.

In order to prevent the cylinder drum 20 from lifting the inclined disk 22, a spring 33 is supported against the bearing of the drive shaft 2 via the support body 34. To this end, the support body 34 has a spherical gap in the area of contact with the bearing of the drive shaft 2, which corresponds to the spherical outer edge 32 of the bearing. The outer diameter of the support body 34 provided as a ring corresponds to the inner diameter of the central drilling portion 31 of the first cylinder drum 20. On the opposite side of the support body 34, a spring 33 is supported against a seeger ring 35 inserted into the groove of the cylinder drum 20. The spring 33 generates an axial force in the axial direction of the cylinder drum, which is applied to the operating surface 25 of the cylinder drum 20 against the support surface 24 of the inclined disk 22. .

A shrink disk 36 is provided to prevent lifting of the piston 16 out of the spherical gap 14 of the carrier plate 13 during the suction stroke. The shrink disk 36 is, for example, screwed into the carrier plate 13 to fix the ball-shaped head 43 of the piston 16 to each spherical gap 14. To this end, the shrink disk 36 has many perforations 37 corresponding to pistons 16 of the same number, the perforations being spherical in outline and coinciding with the periphery of the ball-shaped head 43 of the piston 16. do. To this end, the piston 16 also has a ball shape in the region projecting beyond the spherical gap 14.

The piston 16 has a lubricating oil bore 38 that faces from the bottom 39 of the piston on the ball-shaped head 43 of the piston 16 and extends to the flat end 40. The release of the hydrostatic load on the piston 16 of the segmental connection is achieved by the lubricant bore 38.

The hydrostatic piston mechanism 1 according to the invention can be used both as a pump and as a motor. When used as a pump, the cylinder drums 20, 21 are driven via the tooth system 6. In the illustrated embodiment, the drive shaft 2 and the one-piece carrier plate 13 are set in rotation in accordance with the rotational movement transmitted by the tooth system 6 to the drive shaft 2. The pistons 16, 17, which are connected to the carrier plate 13 in a torsion-proof manner with respect to the rotation about the axis of the drive shaft 2, likewise make a rotation about the axis of the drive shaft 2. The torque is transmitted to the first cylinder drum 20 and the second cylinder drum 21 via the pistons 16, 17, respectively. Accordingly, the cylinder drums 20 and 21 perform a rotational movement about an axis inclined with respect to the axis of the drive shaft 2. In this step, the cylinder drums 20, 21 are held in contact with each of the inclined disks 22, 23 by springs 33, 33 '. As the axis of rotation of the drive shaft 2 is inclined with respect to the cylinder drums 20 and 21, the pistons 16 and 17 perform a stroke-like movement in the corresponding cylinder gaps 18 and 19. This allows the pressure medium to be delivered by varying cylinder volumes while one rotation is transferred to the same hydrostatic circuit or to another hydrostatic circuit.

In the embodiment shown in FIG. 1, the torque required to rotate the cylinder drums 20, 21 is transmitted by the pistons 16, 17 from the carrier plate 13 to the cylinder drums 20, 21, respectively. In this step, each cone portion (41,42) on each piston (16,17) and each cone portion (39) lying between each ball-shaped head (43,44) of the piston (16,17) The pistons 16, 17 perform a tilting motion until 45,46 come into contact with the respective cylinder gaps 18,19.

The piston 16 is provided with the sealing part 41 adjacent to the bottom. The sealing portion 41 has a thin wall structure. In the embodiment shown, the thin wall design of the sealing part 41 is achieved by a gap 65 integral to the piston 16 from the bottom face. The piston 16 is of spherical design located in the sealing portion 41 at its outer circumference. Spherical outlines of this kind can arise, for example, through the integration of the cylinder gap 65 at the bottom of the piston, where a thin walled wall section 66 is used as a contour to achieve the spherical outline. It is.

An alternative to torque transfer between the drive shaft 2 and the cylinder drums 20, 21 is shown in FIG. 2. In FIG. 2, the same reference numerals refer to components already known in FIG. 1. In order to avoid unnecessary repetition, the detailed description of the whole piston mechanism 1 'is not made anymore.

In the embodiment illustrated in FIG. 2, joint elements 50, 51 are provided to transfer the torque between the drive shaft 2 and the cylinder drums 20, 21. The joint elements 50, 51 are torque-transfer devices between the drive shaft 2 and the cylinder drums 20, 21, which are identical in design and operate in the same way. Thus, the following description is limited to the joint element 50 shown on the left in FIG. The joint element 50 has a cylindrical section 52. The cylinder portion 52 is inserted into the gap 53. The depth of the gap 53 is greater than the length of the cylinder portion 52 of the sound element 50. The joint element 50 projects radially beyond the spherical outer portion 32 of the drive shaft 2 bearing, the projecting portion being provided as a radially extended area 54. The end face 55 of the fitting element 50 is likewise contoured in a spherical manner, which is provided on the extension area 54. In the longitudinal axial direction of the fitting element 50, the end face 55 may be connected to the opposite end of the fitting element 50 by a duct 57. The radially extending area 54 is coupled to the groove 56 inside the cylinder drum 20.

As will be described later with reference to FIG. 3, alternatively the duct 57 may be connected to a volume formed in the spherical gap 14 via the connecting duct 58 by the flat end 40 of the piston 16. In the same way, the duct 60 in the joint element 51 may be connected to a corresponding volume enclosed beyond the piston 17 in the spherical gap 15 via the connecting duct 59.

A second alternative embodiment for the sealing portions 41 ′, 42 ′ of the pistons 16, 17 is shown in FIG. 3. In the sealing portion 42 ', the piston 17 is provided as a solid piston 17'. At its end projecting into the cylinder gap 19, the solid piston 17 ′ is likewise provided with a spherical outline 67. The groove 68 is formed in the sealing portion 42 'of the solid piston 17' at the point where the groove 68 is transferred to the cone portion 46. As shown in FIG. A sealing ring 69, which interacts with the wall of the cylinder gap 19 in the manner of sealing, is inserted into the groove 68. The piston ring 69 is preferably made of steel, for example. On its outer surface 70 which interacts with the cylinder gap 19, the piston ring 69 is likewise outlined in a spherical manner.

In the hydrostatic piston mechanism 1, 1 ′ according to the invention, it is advantageous that the cylinder drums 20, 21 in each case are designed in one piece. This significantly reduces the parts of the moving parts with respect to each other, and the high stiffness of the cylinder drums 20, 21 is due to the centrifugal force and also due to the internal pressure of the cylinder gaps 18, 19. ) So that you can absorb it well. Due to the elliptical movement of the sealing portions 41, 41 ′, 42, 42 ′ of each of the pistons 16, 17, the necessary compensating movement of the pistons 16, 17 is the carrier plate 13 and the piston 16. Is produced in a simple manner by the segmental connection between them. To this end, the pistons 16 and 17 are located in the carrier plate 13 by a connection such as a ball joint and are connected to the carrier plate by each of the shrink disks 36 and 36 'to prevent axial movement during the suction stroke. Each is fixed. As a component, under such conditions, the shrink disks 36 and 36 'have a gap 37, 37' in the shrink disks 36 and 36 ', with each ball-shaped head ( 43,44) and their components, forming part of the segmental connections. In each spherical gap 14, 15 the segmental connection of the pistons 16, 17 is allowed to allow slight inclination to the pistons 16, 17 and thereby rotation of the ball-shaped heads 43, 44. Release of the acting hydrostatic load is provided.

As another alternative, the flat side of the radially expanded area 54 of the joint element 50, 51 coupled to the grooves 56, 56 ′ in the cylinder drum 20, 21 is pressure-lubricated. may be lubricated).

In each case, a volume filled with a press medium is formed in the spherical gaps 14, 15 in the carrier plate 13 by the flat ends 40, 40 ′ of the pistons 16, 17, respectively. do. This pressure medium is fed to the ducts 57 and 60 in the joint elements 50 and 51 via the connecting ducts 58 and 59. In each case, the circumferential feed groove 71 is machined into the joint element 50, 51 at the orifice of the connecting ducts 58, 59. The circumferential supply groove 71 allows the duct portion 72 provided in each of the joint elements 50 and 51 to communicate with the respective connecting ducts 58 and 59 reliably. For example, many duct portions 72 are distributed over the circumference of the joint elements 50, 51 and connect the circumferential grooves 71 to the respective ducts 57, 60. It is possible to have a. In this alternative, the ducts 57, 60 in the joint elements 50, 51 are occluded with respect to the end faces 55, 55 ′. The pressure medium supplied to the duct 60 via the connecting duct 59 flows out of the bore 73 in the expansion region 54 ′ of the joint element 51, so that the groove inside the cylinder drum 21 ( 56 ′) ensures that the joint element 51 is pressure-lubricated in surface contact.

The invention is not limited to the illustrated embodiment. Rather, it may be possible to combine the individual features of the embodiments illustrated above with one another in a desired manner.

Included in the description.

Claims (13)

A drive shaft (2) passing through a cylinder drum unit in which cylinder clearances (18, 19) are arranged, in which a piston (16, 17) connected in a torsion-proof manner to the drive shaft (2) is provided; The drum unit is a hydrostatic piston mechanism whose center is located in a bearing (32) provided in the drive shaft, And the cylinder drum unit is installed as a cylinder drum (20, 21) having a plurality of cylinder gaps (18, 19) installed in the cylinder drum unit. The method of claim 1, Hydrostatic piston mechanism, characterized in that the piston (16,17) is connected to the drive shaft (2) via segmental connections (14,43: 15,44). The method of claim 2, The pistons 16, 17 have spherical heads 43, 44 arranged in corresponding spherical gaps 14, 15 in a carrier plate 13 connected to the drive shaft 2. Hydrostatic piston mechanism. The method according to any one of claims 1 to 3, The piston (16, 17) is hydrostatic piston mechanism, characterized in that it has a conical portion (16, 17) disposed between the sealing portion (41, 42) connected to the drive shaft (2). The method according to any one of claims 1 to 4, The cylinder drum (20, 21) is characterized in that it has a hydrostatic stationary center, characterized in that it has a central drilling portion (31, 31`) for interacting with the bearings (32, 32`) of the drive shaft (2) Piston mechanism. The method of claim 5, A hydrostatic piston mechanism, characterized in that the bearings (32, 32 ') of the drive shaft (2) are installed as spherical drive shaft portions. The method of claim 6, At least one joint element 50, 51 is provided in the region of the spherical drive shaft part 32, 32 ′ so that the drive shaft 2 and the cylinder drum 20, 21 are connected to each other in a torsion-proof manner. Hydrostatic piston mechanism, characterized in that. The method of claim 7, wherein Hydrostatic piston mechanism, characterized in that the joint element (50, 51) is fixed to the drive shaft (2) and coupled to the joint groove (56, 56`) inside the cylinder drum (20, 21). The method of claim 7, wherein The joint element (50, 51) is a hydrostatic piston mechanism, characterized in that it is fixed to the cylinder drum (20, 21) and coupled to the joint groove (56, 56`) inside the drive shaft (2). The method according to any one of claims 1 to 9, Hydrostatic piston mechanism, characterized in that the sealing portion (41, 42) having a piston ring is installed on the piston (16, 17). The method according to any one of claims 1 to 10, The piston (16, 17) is hydrostatic piston mechanism, characterized in that it has a spherical outline in the area of the sealing portion (41, 42). The method according to any one of claims 1 to 11, The piston (16, 17) in the region of the sealing portion (41, 42) is characterized in that the hydrostatic piston mechanism having a thin-walled piston shaft that can elastically expand by the cylinder internal pressure. The method according to any one of claims 1 to 12, Hydrostatic piston mechanism, characterized in that the piston (16,17) is fixed in the axial direction by the shrink disk (36,36`).

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